A slender flat coiled spring regulating the movement of the balance wheel in a watch.
（手表内的）游丝，细发条
Example sentencesExamples
In most cases they used a long extension of the hairspring and pinned it to the base of the balance cock.
When the spring is released current ceases to flow in the coil allowing the hairspring to return the balance.
The two hairsprings are offset at 180 degrees to provide optimal balance, better regulation, easy adjustment, improved stability and greater precision.
This oscillation is not exactly a parallel to the balance wheel and hairspring of a clockwork watch, but the fact is that both use oscillations to keep track of passing time.
The curb pins on the regulator must be adjusted so that the hairspring hits them when it is supposed to.
Definition of hairspring in US English:
hairspring
nounˈherˌspriNGˈhɛrˌsprɪŋ
A slender flat coiled spring regulating the movement of the balance wheel in a watch.
（手表内的）游丝，细发条
Example sentencesExamples
The two hairsprings are offset at 180 degrees to provide optimal balance, better regulation, easy adjustment, improved stability and greater precision.
In most cases they used a long extension of the hairspring and pinned it to the base of the balance cock.
When the spring is released current ceases to flow in the coil allowing the hairspring to return the balance.
The curb pins on the regulator must be adjusted so that the hairspring hits them when it is supposed to.
This oscillation is not exactly a parallel to the balance wheel and hairspring of a clockwork watch, but the fact is that both use oscillations to keep track of passing time.